The Rosberg-Hamilton battle has come to an end with the former announcing his departure from the sport. File picture: Hamad I Mohammed / Reuters.

Lewis Hamilton will miss Nico Rosberg next season but he was also one of the few people unsurprised on Friday by his Mercedes team-mate's decision to retire only days after winning the Formula One championship.

"This is the first time he's won (a title) in 18 years, hence why it was not a surprise that he decided to stop," the triple world champion told reporters ahead of the governing FIA's gala prize-giving in Vienna.

"He's also got a family to focus on, and wants more children, and Formula One takes so much of your time. Will I miss the rivalry? Of course."

Rosberg, the 31-year-old son of 1982 champion Keke, won the championship in Abu Dhabi on Sunday and said he decided on Monday that he would go out on top and enjoy time with his wife and baby daughter.

"I've achieved this childhood dream now and I am not willing to do that sort of commitment again for another year. And I am not interested in coming fourth or whatever. I am a fighter and I want to win," said the German.

"So, not interested to do that again, don't want to do it again, and so I have decided to follow my heart and my heart has told me to stop there, call it a day and go on to other things.

"It feels wonderful and it feels right," added Rosberg. "My wife Vivian is also very excited. She'll have her husband back and I'll be a dad again ... which is going to be wonderful."

Hamilton and Rosberg have been friends and rivals since their teenage days in karting, with the Briton beating him to the Formula One championship in 2014 and 2015.

Each has a benchmark for the other throughout their careers, the man they measure themselves against, and Hamilton recognised he would miss the German.

"We started out when we were 13 and we'd always talked about being champions," he said. "When I joined this team, Nico was there, which was again something we talked about when we were kids.

"It's going to be very, very strange and it will be sad not to have him in the team next year. The sport will miss him and I wish him all the best.

"Of course it is a shame that he won't allow me to take it (the title) back or fight to take it back but that is his choice and I respect his decision: go out on top while you can."

Hamilton said he did not care who Mercedes chose as his team-mate, providing they had equal terms.

"It doesn’t matter who... I'll race them, I'm here to race," he said.

WHAT THE OTHERS SAID

Formula One supremo Bernie Ecclestone

"He needs more time to spend his money, that's all"

Mercedes team boss Toto Wolff

"This is a brave decision by Nico and testament to the strength of his character," Wolff said in a team statement. "He has chosen to leave at the pinnacle of his career, as world champion, having achieved his childhood dream. The clarity of his judgement meant I accepted his decision straight away when he told me."

FIA president Jean Todt

"I was privileged to receive a call from Toto Wolff this morning informing me of Nico's decision. I was very surprised, as I'm sure everyone is, but Nico has demonstrated across the year that he is extremely brave.

"I think he did five or six of the hardest laps of his life in the final race of the championship but the consequence is that he made it."

Former racer and Sky Sports F1 commentator Martin Brundle

"I find it absolutely extraordinary, a big surprise... it's obviously a personal decision and it's bad for Formula One because we haven't got a world champion through the winter and next season."

Olympic champion sprinter Usain Bolt

"I can't really understand it but everybody has their reasons, I guess he felt like he's got what he wanted," Bolt told reporters in Monaco ahead of the athlete of the year awards. "When you get where you want to be, if you accomplish your goal, I guess there's no reason to keep going."

Formula One drivers on Twitter

"Definitely a great Champion!!!! Big admiration" - Force India's Sergio Perez.

"Respect my friend! @nico_rosberg" - Haas's Romain Grosjean.

"Big respect" - Danish driver Kevin Magnussen

"Well done Nico. More to life than chasing round in circles. Respect" - 1996 champion Damon Hill

"Nico what a brave very brave decision, he has some very powerful reasons I am sure. Brilliant World Champion.Very interesting for Merc now." - 1992 champion Nigel Mansell.